英语动词有主动语态和被动语态之分。主动语态句子中的主语是动作的执行者,被动语态句子中的主语是动作的承受者。被动语态由“be + v-ed”构成。
一、被动语态用于以下几种情况
1.不知道或没有必要指出动作的执行者。如:
Many new buildings are built in our city.
2.强调动作的承受者。如:
The wounded man has been sent to a hospital.
3.动作执行者有比较长的修饰语。如:
The person was supported by those who wished to have a chance to make friends with him.
4.出于礼貌,不愿说出动作的执行者。如:
You are requested to attend the party.
二、过去分词作表语与被动语态的区别
1.系表结构中的过去分词是表示主语的特征或状态;而被动结构则是表示主语是动作的承受者。试比较:
Our building is surrounded with the trees.(系表)
The film is usually showed on Sunday.(被动)
2.系表结构不能带有by引导的短语;而被动结构中可以用by引导的短语引出动作的执行者。试比较:
The book is well written. (系表)
The book was written by Lu Xun.(被动)
三、使用被动语态应注意的几点
1.带双宾语的主动结构的句子,变为被动语态结构时,只能将其中的一个宾语变为主语,另一个宾语仍要保留。如果保留的是间接宾语,要在间接宾语之前加上介词to或for.如:
We are taught English by her.或English is taught to us by her.
2.主动语态中的不带to的动词不定式作宾补变为被动语态时,要加上不定式符号to.如:
The boss made him work over twelve hours a day.
He was made to work over twelve hours a day.
3.短语动词用于被动语态应作为一个整体,不能丢掉其中的介词或副词。如:
The meeting has been put off.
4.有些及物动词和及物动词短语(多表示“静态”)不能用于被动语态,常见的有have, cost, lack, last, own, hold, fit, agree with等。
5.有些不及物动词以主动形式表示被动意义,常见的有cut, wash, write, sell等。如:
The shirt washes well.